replacing capacitors

[alphye]

Not a technical guy but all I want is to replace the capacitors on the crossover of my FOCAL 726s

























Speakers

 

[ryanosaur]

Why?
You can if you match them up properly.
Do you expect to hear something different?

 

[alphye]

does anyone here know what caps Focal use on this crossover? I dont mean the values (uf or voltage) but what is compatible with the crossover. All i have figured out is that they are Electrolytic Bi polar Radial! There are so many caps used for various applications. I have found caps with the same values I am looking for but do not have a clue whether they are suitable for crossovers or not!!

 

[alphye]

Why?
You can if you match them up properly.
Do you expect to hear something different?

OVERHEATING AMPS CAUSED TWO TO BLOW (one on either speaker) so i thought I might as well change them all

 

[highfigh]

OVERHEATING AMPS CAUSED TWO TO BLOW (one on either speaker) so i thought I might as well change them all

Why are you shouting?

What do you see on the other caps WRT brand? If you use caps from Bennic, you should be fine. You shouldn't need to change all of them.

 

[ryanosaur]

Why are you shouting?

What do you see on the other caps WRT brand? If you use caps from Bennic, you should be fine. You shouldn't need to change all of them.

Yes, Bennic, Audyn Q4, even some of the Daytons.

 

[Eppie]

Changing them all seems a bit of a waste of money. They shouldn't be more than 10 years old. You don't have to match the original brand. Just match the value and voltage rating with a good quality polypropylene capacitor. Audyn and Dayton make good caps for reasonable prices. Jantzen and Mundorf will get pushed by some "audiophiles" but they are overpriced and will not make a measurable difference.

 

[Swerd]

OVERHEATING AMPS CAUSED TWO TO BLOW (one on either speaker) so i thought I might as well change them all

This raises more questions than it answers. Did your amp really overheat, causing the capacitors to fail? Does your amp need repair? Or, is this your just take on what happened? If you replace the blown capacitors, will your damaged amp cause them to fail again? Even worse, if you replace the blown electrolytic bi-polar (often called non-polar electrolytic, or NPE) caps with metalized polypropylene (MPP) caps that are much less likely to fail, will something else fail on your speakers – like one or several of the drivers?

NPE caps are known to fail with age, but that doesn't always happen. And when it does it usually takes a lot longer than 10 years.

I agree completely with the others who posted (above) that any MPP capacitor with the same or similar capacitance value (±10%) can replace the NPE caps that failed in your speakers. They should not ever age or fail. There is no need to pay high prices for the so-called premium audio-grade caps. There is no audible or electronic benefit from them.

You should also be aware that MPP caps will be physically larger than the equivalent NPE cap. If you intend to replace the NPE caps in the existing crossover board in your Focal 726 speakers, you probably won't have the space. Do your crossover boards look like the photo below? The NPE caps Focal used are radial. Both wires come out of one end of the cylinder, allowing them to stand on end instead of lying sideways. Most MPP caps come with one lead on either end. Fitting larger MPP caps on boards like the one in the photo will be trouble. You might be better off by building your own larger board.

 

[slipperybidness]

Not a technical guy but

Clearly this is problem #1

Once you identify the new caps, who is gonna do the actual technical work, removing the old caps and soldering in the new caps?

What was your original problem that blew out your caps?

The last thing you want to do is go rebuild your XO, then blow them out again immediately.

 

[alphye]

This raises more questions than it answers. Electrolytic Bi polar capacitors (often called non-polar electrolytic, or NPE) are known to fail with age, that doesn't always happen. And when it does it usually takes longer than 10 years.

I agree completely with the others who posted (above) that any metalized polypropylene (MPP) capacitor with the same or similar capacitance value (±10%) can replace the caps that failed in your speakers. They should not ever age or fail. There is no need to pay high prices for the so-called premium audio-grade caps. There is no audible or electronic benefit from them.

You should also be aware that MPP caps will be physically larger than the equivalent NPE cap. If you intend to replace the NPE caps in the existing crossover board in your Focal 726 speakers, you probably won't have the space. Do your crossover boards look like this? The NPE caps Focal used are radial. Both wires come out of one end of the cylinder, allowing them to stand on end instead of lying sideways. Most MPP caps come with one lead on either end. Fitting larger MPP caps on boards like that in the photo will be trouble. You might be better off by building your own larger board.
View attachment 53485

yep looks exactly like this! In the meantime ordered Mundorf's Axial Caps (couldnt find Radial anywhere) so it will be a bit of a challenge to connect to this crossover. I changed them all for peace of mind in the sense that I know that from 2022 all caps are new, not say some are +6 years old and the others new The Mundorfs I bought from the PLAIN series are highly recommended (and costly)and as some mentioned I probably wont hear sonic differences but again for peace of mind I know i have quality products that SHOULD bring out the best in my speakers.

 

[alphye]

Clearly this is problem #1

Once you identify the new caps, who is gonna do the actual technical work, removing the old caps and soldering in the new caps?

What was your original problem that blew out your caps?

The last thing you want to do is go rebuild your XO, then blow them out again immediately.

I can solder and desolder but if I get lets say too nervous I can call in a relative who is handy at electronics.
I suspect the caps in both speakers blew (both the same caps associated with the mid range ) due to my amplifier overheating. Dont know what caused that, but i know its been going for 30years without a single problem, then one day one side of an lp at my normal volume (9o'clock) and they are roasting hot. I say they because I was using two power amps and a preamp (Bridged). Turn up volume just a teeney weeny bit and sound is distorted and woofers pounding like mad!! Ordered a new amp anyway, after 30 years !

 

[alphye]

Changing them all seems a bit of a waste of money. They shouldn't be more than 10 years old. You don't have to match the original brand. Just match the value and voltage rating with a good quality polypropylene capacitor. Audyn and Dayton make good caps for reasonable prices. Jantzen and Mundorf will get pushed by some "audiophiles" but they are overpriced and will not make a measurable difference.

I just bought the Mundorfs, yes quite expensive and i am sure I will not hear any sonic difference easpecially with the music (rock ) i listen to! But as i mentioned o another contributor here, i wanted to change them all for peace of mind knowing that from 2022 all caps are new, quality ones.

 

[Swerd]

yep looks exactly like this! In the meantime ordered Mundorf's Axial Caps (couldnt find Radial anywhere) so it will be a bit of a challenge to connect to this crossover. I changed them all for peace of mind in the sense that I know that from 2022 all caps are new, not say some are +6 years old and the others new The Mundorfs I bought from the PLAIN series are highly recommended (and costly)and as some mentioned I probably wont hear sonic differences but again for peace of mind I know i have quality products that SHOULD bring out the best in my speakers.

Too bad you didn't ask here before ordering those Mundorf caps. I hope they weren't terribly expensive.

What capacitance value (microfarads, µF) and voltage rating are they? The capacitance value matters the most. ±10% is OK in crossovers. Voltage ratings refer to the maximum voltage they can withstand before failing. In speaker crossovers, 100V is plenty. Higher voltage ratings will make for a larger cylinder.

Note: Corrections were made here:
Axial and radial mean different wire lead locations on the caps. Radial leads allow a cap to be stood on end. Axial leads are more easily wired if the cap is lying on its side. Electronically they are not different.
A radial cap

An axial cap

 

[Eppie]

I just bought the Mundorfs, yes quite expensive and i am sure I will not hear any sonic difference easpecially with the music (rock ) i listen to! But as i mentioned o another contributor here, i wanted to change them all for peace of mind knowing that from 2022 all caps are new, quality ones.

The one issue you may find is the physical size. Mundorfs are often quite a bit larger than Audyn and as you are replacing a radial capacitor with an axial you will already have a challenge fastening it down. You may find that the Mundorf is simply too big.

 

[ryanosaur]

Ideally, the entire network should be rebuilt... either that or there will be a FSM's worth of hookup wire connecting those new caps, and they won't be attached to anything.

 

[alphye]

Too bad you didn't ask here before ordering those Mundorf caps. I hope they weren't terribly expensive.

What capacitance value (microfarads, µF) and voltage rating are they? The capacitance value matters the most. ±10% is OK in crossovers. Voltage ratings refer to the maximum voltage they can withstand before failing. In speaker crossovers, 100V is plenty. Higher voltage ratings will make for a larger cylinder.

Axial and radial mean the same thing in caps. It depends on who translated it to English.
An axial cap
View attachment 53486
A non-axial cap
View attachment 53487

original 15uf 63v replaced with 22uf 70v, original 70uf 63v, replaced with 82uf 70v, original 170uf 63v replaced with 180uf 63v

 

[alphye]

The one issue you may find is the physical size. Mundorfs are often quite a bit larger than Audyn and as you are replacing a radial capacitor with an axial you will already have a challenge fastening it down. You may find that the Mundorf is simply too big.

yes im aware of the harrowing task ahead but have been chatting to engineers in the uk who have been giving me options. If i cannot install the axial vertically (by bending one lead....and extending the lead if neccessary) I can leave the caps 'in air' (ie leads soldered to the board obviously, but the cap itself elevated over other components as it bis not going to move anyway). I'll see what works best at least now I'm smiling ...

 

[Eppie]

original 15uf 63v replaced with 22uf 70v, original 70uf 63v, replaced with 82uf 70v, original 170uf 63v replaced with 180uf 63v

No, no, no! Do not replace with different micro farad values. You'll change the characteristic of the crossover.

 

[ryanosaur]

original 15uf 63v replaced with 22uf 70v, original 70uf 63v, replaced with 82uf 70v, original 170uf 63v replaced with 180uf 63v

You will be completely altering the performance of those Speakers. This is not advised!.

 

[Swerd]

original 15uf 63v replaced with 22uf 70v, original 70uf 63v, replaced with 82uf 70v, original 170uf 63v replaced with 180uf 63v

Why are you replacing 15 µF with 22 µF? 15 ± 10% = 13.5 to 16.5 µF. Those would be OK. 22 will change the filter too much.

Same for 70 µF vs. 82 µF. Keep it within 10% of the original capacitance value.